Transport systems in cities across the country were put to the test yesterday when passenger flows peaked at the end of the week-long Lunar New Year holiday.

Authorities stepped up the frequency of services, but many people were complaining about how difficult it was to buy train tickets and the heavy traffic congestion.

The peak travel season - which kicked off on January 26 and ends on March 6 - marks the world's largest annual human migration. Up to 220 million passengers are expected to catch trains, and 3.1 billion trips are likely to be made on the nation's roads.

The travel season peaked on February 5, when people rushed back home for family reunions, and yesterday, when they returned to their workplaces.

The Ministry of Railways said that 7.41 million trips would be made as travellers returned to work, prompting the ministry to use 783 additional trains yesterday to cope with the increased passenger flows.

There were 19.8 million vehicles recorded on national highways on Thursday, with traffic on major highways up 21.53 per cent year on year.

Many said travelling during the peak season was a horrible experience. "The travel season is really exhausting," one microblogger said. "It took me seven hours on the road because of serious congestion along the roads. I should have travelled by high-speed train."

Another internet user said: "Terrible, I have to travel for long hours again. The roads got jammed."

Some said they were also frustrated by the difficulties encountered in getting train tickets. Beijing lawyer Xiao Wenbin wrote to the railways ministry, demanding it disclose the number of train tickets available for sale during the holiday travel season. The ministry rejected his demand.